Nu-(2-hydroxyphenylmethylene)-or-gano aryl amines and metal salts thereof



United States Patent Office 3349i iii Patented Oct. 24, 1967 Thisinvention relates to the stabilization of plastics and more particularlyto a novel method of inhibiting deterioration'of plastic caused oyoxidation and ultraviolet light.

It is well known that most, if not all, plastics undergo deteriorationwhen exposed to sunlight and air. The deterioration due to sunlight andthe deterioration due to oxygen are separate phenomena as evidenced bythe fact that either one may occur in the absence of the other. It maybe that deterioration from one source enhances deterioration from theother source. In any event, it is important that both forms ofdeterioration be inhibited and the present invention provides a novelmethod for accomplishing this.

Recent advances in plastic technology have made avail able a largevariety of plastics. A definition of plastic which seems to be acceptedin the industry is that plastic comprises a large and varied group ofmaterials which consist of, or contain as an essential ingredient, asubstance of high molecular weight which, while solid in the finishedstate, in some stage in its manufacture is soft enough to be formed intovarious shapes usually through the application, either singly ortogether, of heat and pressure. Plastics generally are prepared by thecondensation or polymerization of a single monomer or a mixture ofmonomers. The plastic may be classified further as being thermosettingor thermoplastic. Plastics also include solid polymers which, in turn,are defined as substances of high molecular weight composed of repeatingunits and exhibiting unique physical properties including one or more ofhigh tensile strength, elasticity, ability to form fibers, etc. Thepolymers may be classified into two general types as (1) condensationand (2) addition polymers. The condensation polymers may be formed froma single monomer of from different monomeric reactants. An additionpolymer is derived from multiple additions of an unsaturated monomer ormonomers. As hereinbefore set forth, most, if not all, plastics undergodeterioration upon exposure to air and ultraviolet light, and thepresent invention provides a novel method of inhibiting suchdeterioration.

In a preferred embodiment the plastic comprises a solid olefin polymer.This may comprise homopolymers or copolyrners of olefinic hydrocarbonsincluding particularly polyethylene, polypropylene and polybutylene, aswell as copolymers of ethylene and propylene, ethylene and butylene andpropylene and butylene. In addition, solid polymers prepared from one ormore higher molecular weight olefins or mixtures may be stabilized inaccordance with the present invention.

Deterioration of the solid olefin polymers when exposed to sunlight ischaracterized in its early stages by the breaking of the polymer chainand the formation of carbonyl groups. As oxidation continues, thepolymer cracks and loses tensile strength to the point of mechanicalfailure. For example, electrical insulation prepared from solid olefinpolymers will undergo embrittlement, increase of power factor and lossof electrical resistance when used in exposed locations. Other examplesof the use of solid olefin polymers subject to outdoor exposure are inthe preparation of sheets which are used in draping open areas inbuilding construction in order to protect the construction from theeffect of weather and in the manufacture of light weight outdoorfurniture, cover for greenhouses, awnings, etc. It is readily apparentthat the fabricated product must be protected against deteriorationcaused both by sunlight and air.

Another plastic available commercially on a large scale is polystyrene.Polymerization of styrene proceeds rapidly in an emulsion of 5% sodiumoleate solution and results in high molecular Weight polymers. Inanother method styrene is polymerized in the presence of aluminumtrialkyls. In general, polystyrene is thermoplastic which, however, maybe modified by effecting the polymerization in the presence of a smallamount of divinylbenzene. The

polystryene-type resins are particularly useful in the manufacture ofmolded or machine articles which find application in such goods asWindows, optical goods, automobile panels, molded household articles,etc. One disadvantage of polystyrene is its tendency to deteriorate whenexposed to direct sunlight and air for extended periods of time.

Another class of plastics available commercially is broadly classed asvinyl resins and is derived from monomers such as vinyl chloride, vinylacetate, vinylidine chloride, etc. Polyvinyl chloride plastics areavailable commercially on a large scale and undergo deterioration whenexposed to sunlight. Other vinyl type resins include copolymers of Vinylchloride With acrylonitrile, methacrylonitrile, vinylidene chloride,alkyl acrylates, alkyl methacrylates, alkyl maleates, alkyl fumarates,etc.

Other plastics being used commercially on a large scale are in thetextile class and include nylon (polyamide), Perlon L or 6-nylon(polyamide), Dacron (terephthalic acid and ethylene glycol), Orlon(polyacrylonitrile), Dynel (copolymer of acrylonitrile and vinylchloride), Acrilan (polyacrylonitrile modified with vinyl acetate),Saran (copolymer of vinylidine chloride and vinyl chloride), etc. Hereagain, deterioration of the solid polymer occurs due to ultravioletlight and oxidation.

Still other plastics are prepared from other monomers and are availablecommercially. Illustrative examples of such other solid polymers includephenolformaldehyde resins, urea-formaldehyde resins,melamine-formaldehyde resins, acryloid plastics which are derived frommethyl, ethyl and higher alkyl acrylates and methacrylates as monomersused in the polymerization. Also included in the solid polymers are thepolyurethane foams which are becoming increasingly available on a largescale and polyacetals, especially polyformaldehydes, such as Delrin andCelcon.

It is understood that the plastic may be fabricated into any desiredfinished product including moldings, castings, fibers, films, sheets,rods, tubing 01' other shapes.

Rubber is composed of polymers of conjugated 1,3- dienes, either aspolymers thereof or as copolyrners thereof with other polymerizablecompounds, and the rub-hers, both natural and synthetic, are included assolid polymers in the present specifications and claims. Syntheticrubbers include SBR rubber (copolymer of butadiene and styrene), Buna N(copolymer of butadiene and acrylonitrile), butyl rubber (copolymer ofbutadiene and isobutylene), neoprene rubber (chloroprene polymer),Thiokol rubber (polysnlfide), silicone rubber, etc. The natural rubbersinclude hevea rubber, caontchouc, balata, gutta percha, etc. It is wellknown that rubber undergoes deterioration due to oxygen and, whenexposed to direct sunlight for extended periods of time, also undergoesdeterioration from this source.

In one embodiment the present invention relates to a method ofstabilizing plastic normally subject to deterioration by oxidation andUV light which comprises incorporating in said plastic a small butstabilizing concentration of N (2 hydroxyarylmethylene)Y-arylamineinhibitor or metal salt thereof, where Y is selected 3 from the groupconsisting of hydrocarbyl and hydrocarbyloxy of at least three carbonatoms.

In a specific embodiment the present invention relates to a method ofstabilizing solid polymer normally subject to deterioration by oxidationand UV light Which comprises incorporating in said polymer a small butstabilizing concentration of a nickel salt of N-salicylidene-4-alkylaniline in which said alkyl contains from about 5 to about 20carbon atoms.

In another embodiment the present invention relates to plastic subjectto deterioration by oxidation and UV light containing, as an inhibitoragainst such deterioration, a stabilizing concentration of the inhibitorset forth herein.

It is believed that the inhibitors of the present invention are novelcompositions of matter and accordingly are being so claimed in thepresent application. I

The novel inhibitors of the present invention are N- (2hydroxyarylmethylene) Y arylamines and metal salts thereof, the Ysubstituent being as hereinbefore defined. These inhibitors readily areprepared by the reaction of an alkyl or alkoxy aniline withsalicylaldehyde or a substituted salicylaldehyde. This reaction occurswith the liberation of water to form a Schiffs base. In one embodimentthe Schiffs base is used as the inhibitor but, in a preferredembodiment, the metal salt of the Schitfs base is used as the inhibitor.When the metal salt is prepared, it preferably is formed by the.reaction of two mole proportions of the Schiffs base with one moleproportion of a metal, the latter being reacted as a compound of themetal. The salts also may be eX-' pressed as coordination complexes.

Without intending to be limited thereto, it is believed that the metalsalts of the Schiifs bases may be illustrated as shown below. Thestructure shown below is believed to be formed by the reaction of twomole proportions of the Schiffs base, prepared bythe reaction of asubstituted aniline with salicylaldehyde, with one mole proportion of anickel compound.

in which R is alkyl, phenyl, alkylphenyl or alkoxyphenyl.

As hereinbefore set forth, Y in the above formula comprises one or morehydrocarbyl or hydrocarbyloxy groups, at least one of which contains atleast three'and preferably from about five to about twenty carbon atoms.It is understood that the other phenyl nucleus and/or methylene groupsmay contain hydrocarbyl and/or hydrocarbyloxy substituents attachedthereto. in still an- 7 other embodiment, 2 hydroxyacyl-phenones or 2hydroxybenzophenones are used in place of salicylaldehyde for reactionwith the substituted aniline. 7

As hereinbefore set forth, one of the reactants used in preparing thenovel inhibitor of the present invention is a substituted aniline. It isessential that the analine contains at least one hydrocarbyl orhydrocarbyloxy group of at least three carbon atoms and preferably offrom about five to about twenty carbon atoms. Ina preferred embodimentthe substituent is an alkyl group of at least three and preferably offrom five to about twenty carbon atoms. In another preferred embodimentthe substituent is an alkoxy group of at least three and preferably offrom about five to about twenty carbon atoms. In still anotherembodiment the substituent is selected from aralkyl, aryl, alkaryl,alkylcycloalkyl, cycloalkylalkyl, aryloxy, alkaryloxy, arylalkoxy, etc.When only one such substituent is attached to the aniline ring, itpreferably is in the 4-position, although it may be in the 2- or3-positions. When two or more of such substituents are present, at leastone substituent preferably is in the 4-position and the othersubstituent or substituents will be in the 2-, 3-, 5- and/or6-positions. While the substituted aniline is preferred, it isunderstood that, in another embodiment of the invention, thecorrespondingly substituted naphthylamine may be used for reaction withsalicylaldehyde or substituted salicylaldehyde, but not necessarily withequivalent results.

The substituted aniline is reacted with salicylaldehyde or a substitutedsalicylaldehyde. Here again, the substituents are selected fromhydrocarbyl and hydrocarbyloxy groups and more particularly thosehereinbefo-re specifically set forth in the previous paragraph.Particularly preferred reactants in this embodiment includesalicylaldehyde and ortho-vanillin (2-hydroxy-3-methoxybenzaldehyde). Inanother embodiment the substituted salicylaldehyde comprises aZ-hydroxyaryl alkyl ketone as illustrated by 2 -hydroxyacetophenone,Z-hydroxypropiophenone, 2-hydroxybutyrophenone, 2-hydroxyva'lerophenone,

2-hydroxycaprylophenone, 2-hydroxylaurylphenone,2-hydroxypalmitylphenone, etc. In still another embodiment, thesubstituted salicyaldehyde comprises 2-hydroxybenzophenone,Z-hydroxy-4-alkylbenzophenone, Z-hydroxy- 4'-alkylbenzophen-one,2-hydroXy-4-alkoxybenzophenone, Z-hydoxy-4-alkoxybenzophenone, etc.

The reaction of the substituted aniline and salicylaldehyde orsubstituted salicylaldehyde is effected in any suitable manner. Whilethe reaction may be effected at room temperature or slightly above, itgenerally is preferred to effect the reaction at refluxing conditions.The exact temperature will depend upon the particular solvent employed.For example, when benzene is used as the solvent, the temperature isabout C. correspondingly higher refluxing temperatures are employed whenusing toluene, xylene, ethyl benzene, cumene, etc., as the solvent. Inanother embodiment an alcohol solvent is used including methanol,ethanol, propanol, butanol, etc., or other oxygenated solvents asethers, glycols, etc., may be used. In general, the reaction temperaturewill be within the range of from room temperature or slightly higher to200 C. or more. Higher temperatures which may range up to 300 C. may beemployed when the reaction is effected under superatmospheric pressurewhich may range from 10 to 1000 pounds per square inch or more. Whendesired, the substituted aniline and/ or salicylaldehyde compound may beprepared as separate solutions in a solvent and introduced in thismanner into the reaction zone, or either one or both of these compoundsmay be introduced into the reaction zone and the solvent separatelysupplied thereto. The refluxing and/or stirring of the heated reactantsis continued for a time sufiicient to effect substantially completereaction, which time may range from 0.1 to 10 hours or more. In thisreaction, water is formed and preferably is continuously removed fromthe reaction zone. Following completion of the reaction, the resultantSchiifs base may be separated from the solvent or may be allowed toremain in solution.

In a particularly preferred embodiment the metal salt of the Schiifsbase is used as the inhibitor. Any suitable metal salt may be used, thenickel salt being preferred. Other metals include copper, cobalt,lithium, antimony, cadmium, lead, tin, uranium (U0 vanadium, zinc, iron,mercury, etc. Any suitable metal compound is used in preparing the salt.A preferred compound of nickel is nickel chloride. Other soluble saltsof nickel include nickel acetate tetrahydrate, nickel bromidetrihydrate, nickel carbonyl, nickel chloride hexahydrate, nickelformate, nickel nitrate hexahydrate, nickel sulfate hexahydrate,

etc. A preferred copper compound is cupric acetate hyacetoacetate,cupric formate, cupric nitrate trihydrate,

cupric nitrate hexahydrate, cupric salicylate, etc. A preferred compoundof cobalt is cobaltous sulfate monohydrate. Other soluble compounds ofcobalt include cobaltous acetate, cobaltous bromide, cobaltous chloride,cobaltous iodide, cobaltous nitrate, etc.

The Schiffs base is reacted With the metal compound in any suitablemanner. For example, the Schifts base in alcoholic solution is firstreacted with an alkali metal hydroxide alcoholic solution and then isreacted with nickel chloride. The reaction temperature generally will bein the range of from about 20 C. to refluxing temperature which may beas high as 200 C. In certain cases, it is unnecessary to first reactWith an alkali metal hydroxide as, for example, When the lithium salt isprepared. Preferred alkali metal hydroxides comprise sodium hydroxideand potassium hydroxide, although other alkali metal hydroxide solutionsmay be used, as Well as calcium, magnesium. strontium or bariumhydroxides.

The substituted aniline and salicylaldehyde compounds are reacted inequal mole proportions, with the liberation of one mole proportion ofwater. When desired, an excess of one of the reactants may be present inorder to assure complete reaction. The resultant Schiffs base preferablyis reacted in a proportion of two moles thereof per one mole of themetal compound. Here again, an excess of one of the reactants may bepresent to assure complete reaction. The alkali metal hydroxide is usedin an equal mole proportion to the Schiffs base, although an excess maybe used in order to assure complete reaction.

It is believed that the reaction proceeds first by the formation of theSchiifs base, then the replacement of the hydrogen with the alkali metalon the hydroxyl group and subsequent formation of the metal salt byreaction with the nickel compound. For example, 4-octylaniline isreacted With salicylaldehyde to form N-salicylidene-4-octylaniline. Thisreacts With sodium hydroxide to form the corresponding salt.Subsequently, the sodium is removed by reaction with nickel chloride,for example, to form sodium chloride and the coordination complex ornickel salt.

As hereinbefiore set forth, the inhibitors of the present invention areN-(Z-hydroxyarylmethylene)-Y-arylamines and metal salts thereof.Illustrative compounds include N-salicylidene-4-propylaniline,N-salicylidene-4-butylaniline, N-salicylidene-4-pentylaniline,N-salicylidene-4-hexylaniline, N-salicylidene-4-hepty1aniline,N-salicylidene 4-octylaniline, N-salicylidene-4-nonylaniline,N-salicylidene-4-decylaniline, N-salicylidene-4-undecylaniline,N-salicylidene-4-dodecylaniline, N-salicylidene-4-tridecylaniline,N-salicylidene-4-tetradecylaniline, N-salicylidene-4-pentadecylaniline,N-salicylidene-4-hexadecylaniline, N-salicylidene-4-heptadecylaniline,N-salicylidene-4-octadecylaniline, N-salicylidene-4-nonadecylaniline,

N-salicylidene 4-eicosylaniline, etc.,

corresponding compounds in which the alkyl group is in the 2-position,corresponding compounds in which the alkyl group is in the 3-position,corresponding compounds containing two alkyl groups in the 2,4- or3,4-positions on the aniline ring etc.,

N-salicylidene-4-propoxyaniline, N-salicylidene-4-butoxyaniline,N-salicylidene-4-pentoxyaniline, N-salicylidene-4-heicoxyaniline,N-sa1icylidene-4-heptoxyani1ine, N-salicylidenel-octoxyaniline,N-sa1icylidene-4-nonoxyaniline,

N-sa1icylidene-4decoxyaniline, N-salicylidene-4-undecoxyaniline,N-sa1icylidene-4-dodecoxyaniline, etc.,

corresponding compounds in which the alkoxy group is in the 3-position,corresponding compounds containing two alkoxy groups in the 2,4- or3,4-positions on the aniline ring, etc., corresponding compoundscontaining one alkyl and one alkoxy group, corresponding compounds inwhich the alkyl and/or alkoxy group is replaced by an aralkyl, aryl,alkaryl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, etc.,substituent. The alkyl group may be a straight chain substituent orbranched in varying degree. The attachment to the aromatic nucleus maybe on the terminal carbon atom or on one of the internal carbon atoms.Additional illustrative compounds include N-[ (2-hydroxyphenyl) (methyl)methylene] -4-propylaniline,

N-[ (2-hydroxyphenyl) (methyl)methylene] -4-butylaniline,

N-[ (Z-hydroxyphenyl) (methyl) methylene] -4-pentylaniline,

N-[ (Z-hydroxyphenyl) (methyl) methylene] -4-hexylaniline,

N-[ (Z-hydroxyphenyl) (methyl) methylene] -4-heptylaniline,

N-[ (Z-hydroxyphenyl) (methyl) methylene] -4-octylaniline,

N-[ (Z-hydroxyphenyl) (methyl) methylene] -4-nonylaniline,

N-[ (Z-hydroxyphenyl) (methyl)methylene] -4-decylaniline,

N-[ (Z-hydroxyphenyl) (methyl) methylene] -4-undecylaniline,

N-[ Z-hydroxyphenyl) (methyl) methylene] -4-dodecylaniline, etc.,

corresponding compounds in which the methyl group is replaced by ahigher alkyl group selected from ethyl, propyl, butyl, pentyl, hexyl,heptyl, octyl, nonyl, decyl, undecyl, dodecyl, etc., correspondingcompounds in which the aniline ring contains two or three alkyl groupspreferably selected from those specifically recited herein,corresponding compounds in which the aniline ring contains alkoxy,aryloxy and/or cycloalkoxy substituents, corresponding compounds inwhich the ring attached to the methylene group also contains one or morealkyl, alkoxy, aryloxy and/or cycloalkoxy substituents. The firstcompound listed above is prepared by the reaction of2-hydroxyacetophenone with 4-propylaniline. The remaining compounds inthe above list are prepared in substantially the same manner except thatthe corresponding reactants will be used' Also, when desired, in placeof Z-hydroxyacetophenone, one will use Z-hydroxypropiophenone, 2-hydroxybutyrophenone, etc.

In still another embodiment the inhibitor is prepared by the reaction ofthe substituted arylamine with a benzoplhenone. Illustrative compoundsin this embodiment inc ude N Z-hydroxyphenyl) (phenyl methylene]-4-propylaniline,

N-[ (Z-hydroxyphenyl) (phenyl) methylene] -4-butylaniline,

N-[ (Z-hydroxyphenyl) (phenyl methylene] -4-pentylaniline,

N-[ (Z-hydroxyphenyl) (phenyl) methylene] -4-hexylaniline,

N-[ Z-hydroxyphenyl) (phenyl methylene] -4-heptylaniline,

N- (Lhydroxyphenyl) (phenyl)methylene] -4-octylaniline,

N-[ Z-hydroxylphenyl) (phenyl methylene] -4-nonylaniline,

N-[ Z-hydroxyphenyl) (phenyl methylene] -4-decylaniline,

N-[ Z-hydroxyphenyl) (phenyl) methylene] -4-undecylaniline, N-(Z-hydroxylphenyl) (phenyl) methylene] -4-dodecylaniline, etc.,

corresponding compounds in which the aniline ring contains two or threealkyl groups preferably selected from those specifically recited herein,corresponding compounds in which the aniline ring contains alkoxy,aryloxy and/ or cycloalkoxy substituents, corresponding compounds inwhich the aniline ring contains one alkyl and one alkoxy group,corresponding compounds in which one or both of the benzophenone ringscontain one or more alkyl, alkoxy, aryloxy and/ or cycloalkoxysubstituents. The first compound in the above list is prepared by thereaction of 4- propylaniline with 2-hydroxybenzophenone. Here again, theother compounds in the list will be prepared in substantially the samemanner except that the corresponding reactants will be used.

As hereinbefore set forth, another embodiment of the invention comprisesthe metal salts of the specific compounds enumerated above. A preferredmetal salt comprises the nickel salt. Other preferred salts comprise thelithium salt, copper salt and cobalt salt. Still other metals have beenset forth hereinbefore. In the interest of simplicity, the metal saltsof the specific compounds recited above are not repeated here, but it isunderstood that the. metal salts of the specific compounds hereinbeforeset forth are definitely comprised as part of the present invention.

From the above description, it will be seen that a number of diiferentcompounds and salts thereof may be prepared and used in accordance withthe present invention. However, all of these are not necessarilyequivalent in the same or different plastic.

In addition to serving to inhibit deterioration of plastic due tooxidation and ultraviolet light, the additives of the present inventionalso serve as mold release agents, anti-blocking agents, anti-staticagents, dyeing aids, etc. These additional advantages are of importancein the manufacture and use of the plastics.

While the compounds described herein are particularly useful for thestabilization of plastics, it is understood that these compounds,including the metal salts, also will have utility in other applications.For example, the metal salts of some of these compounds act asanti-knock agents to increase the anti-knock properties of gasoline.Also, some of these compounds are useful as additives to other organicsubstrates which may include kerosene, lubricating oil, fuel oil,grease, asphalt, adhesives, paints, etc. The compounds also are usefulas catalysts, especially in the formation of acrylic esters from carbonmonoxide, acetylene and alcohol.

The inhibitor of the present invention is incorporated in the plastic orother substrate in a stabilizing concentration which may range fromabout 0.05% to about 10% by weight and preferably from about 0.5% toabout 2% by Weight of the substrate. The inhibitor may be in--corporated in the plastic in any suitable manner and at any suitablestage of preparation. Because the inhibitor may inhibit polymerizationof the monomer, it generally is preferred to incorporate the inhibitorafter the plastic is formed. In one method the plastic is recovered aspowder, pellets, cylinders, spheres, sheets, rolls, bars, etc., andthese may be commingled with the inhibitor in any suitable manner suchas by partly melting the plastic and adding the inhibitor to the hotmelt. This is readily accomplished, for example, by heating the plasticon a steam heated two-roll mill of conventional commercial design andadding the inhibitor during this operation. The plastic containing theinhibitor is recovered in sheet form and may be fabricated in anydesired manner. In another method, the inhibitor is added in a Banburymixer an extruder or in any other suitable manner. When fibers aredesired, the inhibited plastic is recovered from the Banbury mixer andis extruded through a spinnerette.

The inhibitor is utilized as such or is'prepared as a solution in asuitable solvent including alcohols, and particularly methanol, ethanol,propanol, butanol, etc., hydrocarbons and particularly benzene, toluene,xylene, cumene, etc. However, the solvent must not be detrimental to theplastic and, therefore, a preferred solvent comprises the same solventused during the manufacture or working of the plastic. It is understoodthat the inhibitor also may be used along with other additivesincorporated in plastics for various purposes. For example, in coloredplastics carbon black is used in a concentration of below about 5% byweight and generally of from about 1% to about 3% by weight. Similarly,pigments, zinc oxide, titanium oxide, etc., may be incorporated inplastics, the oxides usually being employed in a concentration of fromabout 2% to about 10% by weight. In many cases, silicates, dyes and/orfillers also are incorporated in the plastic.

It is understood that the inhibitor of the present invention also may beused along with other inhibitors or other ultraviolet light stabilizers.The other inhibitors generally will be of the phenolic or amine type andmay include phenyl-alpha-naphthylamine, phenyl-beta-naphthylamine,phenothiazine, Nonox WSP, Nonox C1, dialkylated phenols, trialkylatedphenols, Santonox R, Santowhite, alkyl-alkoxyphenols, 2246 and 425(American Cyanamid), diphenyl-p-phenylenediamine, 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)-butane, 703 (Ethyl Corporation),Salol (salicylic acid esters), p-octylphenylsalicylate, various phosgenealkylated phenol reaction products, variousalkoxyalkyldihydroxybenzophenones, polyalkyldihydroxybenzophenones,'tetrahydroxybenzophenones, 2,4,S-trihydroxybutyrophenone, etc. Otherultraviolet light stabilizers include nickel-bis-dithiocarbamates,nickel-bis-dihydroxypolyalkylphenol sulfides, dilaurylbeta-mercaptodipropionate, dihydroxytetraalkyl sulfides,dihydroxytetraalkyl methanes, various trithiophosphites astrilaurylthiophosphite, dialkylphosphites, trialkylphosphites, highmolecular weight nitriles, various Mannich bases, etc.

The following examples are introduced to illustrate further the noveltyand utility of the present invention but not with the intention ofunduly limiting the same.

EXAMPLE 1 The compound of this example is N-salicylidene-4-dodecylaniline and was prepared by the reaction of 4- dodecylanilinewith salicylaldehyde. This preparation was made by refluxing a mixtureof 65.25 g. (0.25 mole) of dodecylaniline, 30.5 g. (0.25 mole) ofsalicylaldehyde and 200 g. of benzene. 4.5 cc. of water was collected infour hours, which corresponds to the theoretical amount of water whichshould be liberated in this reaction. Following completion of thereaction, the benzene was removed by distillation under vacuum. 77 g. ofN-salicylidene-4-dodecylaniline were recovered as a yellow viscousliquid. Analysis indicated a basic nitrogen of 2.85 meq./ g. and a basicequivalent weight of 352 which corresponds to the theoretical weight of365.

EXAMPLE 2 This example describes the preparation of the nickel salt ofN-salicylidene-4-dodecylaniline prepared as described in Example 1. Thenickel salt was prepared by partially dissolving 36.5 g. (0.10 mole) ofN-salicylidene- 4-dodecylaniline in 200 g. of methanol and addingthereto 6.5 g. (0.10 mole) of potassium hydroxide dissolved in g. ofmethanol. The mixture was stirred and formed a homogeneous yellowsolution. Then 11.89 g. (0.05 mole) of nickelous chloride dissolved ing. of hot methanol were added dropwise to the mixture with intimatestirring. The nickel salt of N-salicylidene-4dodecylaniline formed as agreen precipitate, and was removed from the liquid menstruum and washedboth with hot water and then with methanol. The powder had a meltingpoint of 9295 C.

and a nickel content of 8.25% which corresponds to the theoreticalnickel content of 7.43%.

EXAMPLE 3 N-salicylidene-4-nonylaniline was prepared by refluxing 54.25g. (0.25 mole) of 4-nonylaniline, 30.50 g. (0.25 mole) ofsalicylaldehyde and 200 g. of xylene for six hours. A total of 4.3 cc.of water was collected. Following completion of the reaction, the xylenewas removed by distillation under vacuum. A yield of 84% by weight ofthe theoretical was obtained. The product had a basic nitrogen contentof 3.01 meq./g. and an equivalent weight of 333 which corresponds to thetheoretical weight of 323.

EXAMPLE 4 The nickel salt of N-salicylidene-4-nonylaniline, pre pared asdescribed in Example 3, was prepared by commingling 33 g. (0.10 mole) ofN-salicylidene'4-nonylaniline dissolved in 150 g. of methanol with 6.5g. (0.10 mole) of potassium hydroxide dissolved in 75 g. of warmmethanol. The mixture was vigorously mixed and then heated to reflux. Tothe refluxing mixture there was added dropwise 11.89 g. (0.05 mole) ofnickelous chloride dissolved in 100 g. of warm methanol. The nickel saltprecipitated and was removed from the liquid menstruum. The nickel saltwas analyzed and found to have a nickel content of 7.16% by Weight whichcorresponds to the theoretical nickel content of 8.3%.

EXAMPLE 5 This example describes the preparation ofN-salicylidene-4-sec-butylaniline and was prepared by refluxing 78 g.(0.5 mole) of 4-sec-butylaniline, 61 g. (0.5 mole) of salicylaldehydeand 200 g. of benzene for three hours. 9 cc. of water was collectedwhich corresponds to the theoretical amount of water which should beliberated in the reaction. Following completion of the reaction, benzenewas removed by distillation under vacuum andN-salicylidene-4-secbutylaniline was recovered as an orange coloredliquid.

EXAMPLE 6 This example describes the preparation of the nickel salt ofN-salicylidene-4-sec-butylaniline prepared as described in Example 5.The nickel salt was prepared by dissolving 25.3 g. (0.10 mole) ofN-salicylidene-4-sec-butylaniline dissolved in 150 g. of methanol andintimately mixing to form a homogeneous orange solution. To thissolution was added 6.5 g. (0.10 mole) of potassium hydroxide dissolvedin 75 g. of warm methanol with continued stirring, following which 11.89g. (0.05 mole) of nickleous chloride dissolved in 75 g. of warm methanolwere added dropwise. Intimate mixing was continued. The nickel salt ofN-sa1icylidene-4-sec-butylaniline was recovered as a light green solid.

EXAMPLE 7 The compound of this example is N-o-vanillidene-4-dodecylaniline and was prepared by the reaction of 65 g. (0.25 mole) of4-dodecylaniline with 38 g. (0.25 mole) of o-vanillin in the presence of200 g. of toluene. The reaction was effected at 120 C. for 2.5 hours and4.5 cc. of water was collected. This corresponds to the theoreticalamount of water. The toluene was removed by distillation under vacuumand the product was recovered as an orange-red oil. The yield of 97 g.of product corresponds to 98% of the theoretical yield. The product hada basic nitrogen content of 2.44 meq./ g. and an equivalent weight of413.

EXAMPLE 8 The nickel salt of N-o-vanillidene-4-dodecylaniline, preparedas described in Example 7, was prepared by reacting 39.5 g. (0.10 mole)of the N-o-vanillidene-4- dodecylaniline dissolved in 150 g. of methanolwith 6.5 g.

(0.10 mole) of potassium hydroxide dissolved in 75 g. of warm methanol.The reaction was effected with intimate stirring and heating to reflux.Then 11.89 g. (0.05 mole) of nickelous chloride dissolved in 75 g. ofwarm methanol were added gradually to the refluxing mixture. Refluxingand mixing was continued for two hours, after which the product wasrecovered by vacuum filtering and precipitation with water. The nickelsalt was recovered as a greenyellow solid having a melting point of 8791C. and a percent nickel of 6.81 which corresponds to the theoreticalnickel content of 6.95%.

EXAMPLE 9 The compound of this example is N[(2-hy-droxyphenyl)(methyl)methylene] -4-dodecylaniline and was prepared by the reaction of27.2 g. (0.20 mole) of 2-hydroxyacetophenone with 5212' g. (0.20 mole)of 4dodecylaniline in xylene solvent at 180 C. for six hours, 3.2 cc. ofwater was collected. Following completion of the reaction, the xylenewas removed by distillation under vacuum and N-[ (2-hydroxyphenyl)(methyl methylene 4-dodecylaniline was recovered as a red-yellow oilhaving a basic nitrogen of 2.78 meq./ g. and a basic molecular weight of359 which corresponds to the theoretical molecular weight of 379.

EXAMPLE 10 The nickel salt of N-[Z-hydroxyphenyl) (methyl)-methylene]-44iodecylaniline, prepared as described in Example 9, wasprepared by reacting 37.9 g. (0.10 mole) of this Schifls base mixed with200 g. of methanol with 6.5 g. (0.10 mole) of potassium hydroxidedissolved in g. of warm methanol. The mixture was heated to reflux and11.89 g. (0.05 mole) of nickelous chloride dissolved in g. of warmmethanol were added dropwise thereto. Refluxing was continued for twohours, after which the product was washed with warm water and warmmethanol. The nickel salt was recovered as a lightgreen precipitatehaving a melting point of 193-195 C. and a nickel content of 12.79%.

EXAMPLE 1 l N-[(2 hydroxy 4 methoxyphenyl)(phenyl)methylene]-4-dodecylaniline was prepared by refluxing 45 g.(0.20 mole) of 2-hydroxy-4-methoxybenzophenone, 52.2 g. (0.20 mole) of4-dodecylaniline and 200 g. of xylene. After completion of the reaction,the xylene was removed by distillation under vacuum and the product wasrecovered as a red colored liquid having a basic nitrogen of 1.81 meq./g.

EXAMPLE 12 The nickel salt of N-[(Z-hydroxy-4'rnethoxyphenyl)-(phenyl)methylene]-4-dodecylaniline, prepared as described in Example11, was prepared by reacting 47.1 g. (0.10 mole) of this Schifis basemixed with 100 g. of methanol and 6.5 g. (0.10 mole) of potassiumhydroxide dissolved in 100 g. of warm methanol. This reaction waseffected by heating to refluxing temperature and then 11.89 g. (0.05mole) of nickelous chloride dissolved in 100 g. of warm methanol wereadded gradually to the refluxing mixture. Reflux was continued for twohours. The nickel salt was recovered as a light-green solid having amelting point of 168177 C. and a nickel content of 6.6%.

EXAMPLE 13 N-salicylidene-4-pentoxyaniline was prepared by refiuxing 33g. (0.184 mole) of 4-pentoxyaniline, 22.45 g. (0.184 mole) ofsalicylaldehyde and 100 g. of benzene for eight hours. 3.3 cc. of waterwas collected which corresponds to the theoretical amount of water.After completion of the reaction, the benzene was removed by vacuumdistillation and the product was recovered, after crystallization frommethanol-water, as a solid having a basic nitrogen of 3.5 meq./g. and anequivalent weight of 283, which corresponds to the theoretical weight of283.

1 1 EXAMPLE 14 The nickel salt of N-salicylidene-4-pentoxyaniline,prepared as described in Example 13, was prepared by dissolving 18.8 g,4 mole) of N-salicylidene-4-pentoxyaniline in 200 g. of methanol andgradually adding thereto 4.32 g. mole) of potassium hydroxide dissolvedin 75 g. of warm methanol. The mixture was stirred at room temperatureand then 7.98 g. mole) of nickelous chloride dissolved in 75 g. of warmmethanol were added gradually thereto with continued stirring. A solidgreen precipitate was recovered by filtering, washing and distillation.The nickel salt was recovered as a green solid having a melting point of95101 C.

EXAMPLE 15 Nsalicylidene-4-decyloxyaniline was prepared by refiuxing amixture of 25.13 g. (0.10 mole) of 4-decyloxyaniline, 12.2 g. (0.10mole) of salicylaldehyde and 200 g. of xylene for four hours. 1.8 cc. ofwater was collected, which corresponds to the theoretical amount ofwater. Xylene was removed by vacuum distillation and the product wasrecovered by crystallization. N-salicylidene- 4-decycloxyaniline wasrecovered as a yellow solid having a melting point of 75-80 C., a basicnitrogen of 2.78 meq./g. and an equivalent weight of 358, whichcorresponds to the theoretical weight of 353.

EXAMPLE 16 The nickel salt of N-salicylidene-4decyloxyaniline, preparedas described in Example 15, was prepared by reacting 14.1 g. mole) ofN-salicylidene-4-decyloxy aniline with 2.6 g. mole) of potassiumhydroxide and then with 4.75 g. mole) of nickelous chloride. Methanolwas used as a solvent in this reaction. The nickel salt was recovered asa dark green oil in a yield of 85%.

EXAMPLE 17 The compound of this example is N-salicylidene-4-dodecyloxyaniline and was prepared by refluxing 70.7 g. (0.25 mole) of4-dodecyloxyaniline, 30.5 g. (0.25 mole) of salicylaldehyde and 200 g.of benzene. Refluxing was continued for three hours and 4.5 cc. of waterwas collected, which corresponds to the theoretical amount of water.Following completion of the reaction, the product was recovered asyellow crystals having a melting point of 707l C. and a basic nitrogenof 2.68 meq./g. and an equivalent weight of 373, which corresponds tothe theoretical weight of 381.

EXAMPLE 18 The nickel salt of N-salicylidene-4-dodecyloxyaniline,prepared as described in Example 17, was prepared by first mixing 38.1g. (0.10 mole) of N-salicylidene-4-dodecyl-oxyaniline with 200 g. ofmethanol, stirring and heating to reflux temperature. Then 6.5 g. (0.10mole) of potassium hydroxide in 100 g. of methanol were gradually addedto the mixture and heating and stirring was continued. Following this,11.89 g. (0.05 mole) of nickelous chloride in 75 g. of warm methanolwere added gradually with continued mixing and refluxing. Followingcompletion of the reaction, the nickel salt was recovered as a greensolid.

EXAMPLE 19 The compound of this example is N-[(2-hydroxyphenyl)(methyl)methylene]-4-dodecyloxyaniline and was prepared by refiuxing27.2 g. (0.20 mole) of 2-hydroxyacetophenone, 56.6 g. (0.20 mole) of4-dodecyloxyaniline and 100 g. of xylene for about seven hours. 3 cc. ofwater was collected. The product was recovered as a tan colored solidhaving a melting point of 4753 C., a basic nitrogen of 2.52 meq./g. andan equivalent weight of 397, which corresponds to the theoretical weightof 395.

1 2 EXAMPLE 2o The nickel salt of N-[(2-hydroxyphenyl) (methyl)-methylene]-4-dodecyloxyaniline, prepared as described in Example 19, wasprepared by reacting 19.8 g. (0.05 mole) of this Schifis base with 3.25g. (0.05 mole) of potassium hydroxide and then reacting with 5.95 g.(0.025 mole) of nickelous chloride by intimately mixing at roomtemperature for about one hour. Methanol was used as a solvent in thereaction mixture. The nickel salt was recovered as a light green solidhaving a melting point of 270285 C. and a nickel content of 7.46%.

EXAMPLE 21 The cobalt salt of N-salicylidene-4-dodecylaniline wasprepared by reacting 18.25 g. (0.05 mole) ofN-salicylidene-4-dodecylaniline with 3.25 g. (0.05 mole) of potassiumhydroxide and then with 4.325 g. (0.25 mole) of cobalt sulfate dissolvedin 250 g. of hot water. The cobalt salt was recovered as a black tarrymaterial. Analysis showed this product to contain 5.92% of cobalt.

EXAMPLE 22 The copper salt of N-salicy1idene-4-propylaniline is preparedby reacting one mole proportion of N-salicylidene- 4-propylaniline withsodium hydroxide and then reacting with 0.5 mole proportion of cupricacetate. The copper salt is recovered as the precipitate after vacuumfiltration and washing with warm water and warm methanol.

EXAMPLE 23 The nickel salt of N-sa1icylidene-4-dodecylaniline, preparedas described in Example 2, was evaluated as an inhibitor in a specialbatch of commercial solid polypropylene. This special batch of solidpolypropylene was obtained free of any inhibitors in order that it maybe used as a proper control sample to evaluate the effect of differentinhibitors.

The solid polypropylene used in this example is stated to have thefollowing properties:

TABLE 1 Specific gravity 0.9100.920 Refractive index, n 1.510 Heatdistortion temperature, F.:

At 66 p.s.i. load 240 At 264 p.s.i. load Tensile yield strength, p.s.i.(ASTM D638 5ST) (0.2" per min.) 4700 Total elongation, percent 300-400Stiifness flexural (ASTM D747-50) 10 p.s.i. 1.8 Shore hardness (ASTMD67655T) 74D In one method the solid polypropylene was evaluated in anAtlas type DL-TS Weather-Ometer. The Weather- Ometer may be operatedwith or without the use of water sprays to simulate accelerated moistweathering. In the present runs, the water sprays were not used, therebysimulating and accelerating the effect of hot airy weathering.Polypropylene pellets were milled in a two-roll heated mill ofconventional commercial design and the inhibitor was incorporated in thesamples during the milling. The samples were pressed into sheets of 17mil. thickness and cut into plaques of 1% x l /z. The plaques then wereinserted into plastic holders, aflixed onto a rotating drum and exposedto carbon arc rays at about 52 C. in the Weather-Ometer. Periodicallysamples of the polypropylene were subjected to infrared analysis and theintensity of the carbonyl band at 1715 cm.- was determined and expressedas carbonyl number. As hereinbefore set forth, the formation of,carbonyl groups is an indication of deterioration of the polyolefin. Thehigher intensity of the carbonyl band indicates a higher carbonylconcentration (expressed as carbonyl number) and accordingly increaseddeterioration. The number of hours required to effect an increase incarbonyl content of 100 numbers is taken as the Induction Period.

Samples of the polypropylene also were evaluated by outdoor exposure.The plaques of polypropylene prepared in the above manner were exposuredto weathering on an outdoor rack facing south and inclined at a 45 angleat Des Plaines, Ill. The samples were analyzed for carbonyl formation inthe manner described in the previous paragraph. Here again, the numberof days required to effect an increase in carbonyl content of 100members is taken as the Induction Period.

The results of evaluations in the Weather-Ometer and outdoorexposure arereported in the following table for a sample of the polypropylenewithout added inhibitor and for a sample containing 1% by weight of thenickel salt of N-salicylidene-4-dodecylaniline.

TABLE 2 Weather-Ometer Outdoors Additive Induction Period InductionPeriod (Hours) y None 48 54 1% by wt. of nickel salt of N-salicylidene-a-dodecylaniline 1, 248 207 From the data in the abovetable, it will be seen that this inhibitor was effective in retardingdeterioration of the polypropylene.

EXAMPLE 24 The nickel salt of N-salicylidene-4-nonylaniline, prepared asdescribed in Example 4, also was evaluated in another sample of thepoly-propylene described in Example 23. The results of these evaluationsare reported in the following table. For comparative purposes, theresults using the polypropylene without the inhibitor are repeated inthe table.

TABLE 3 Weather-Ometor Outdoors Additive Induction Period InductionPeriod (Hours) (Days) Nona"... 48 54 1% by wt. of nickel salt of N-salicylidenci-nonylaniline 1, 344 168 The nickel salt ofN-o-vanillideneA-dodecylaniline, prepared as described in Example 8,also was evaluated in another sample of the polypropylene described inExample 23. The results of these evaluations are reported in thefollowing table. Here again, the results of the evaluations made withthe polypropylene without the inhibitor are repeated for comparativepurposes.

TABLE 4 Weather-Ometer Outdoors Additive Induction Period InductionPeriod (Hours) (Days) None 48 54 1% by wt. of nickel salt of N-o-vanillidenc-4-dodecylaniline 1, 440 207 Here again, it will be notedthat the inhibitor served to decrease deterioration of thepolypropylene.

1 4 EXAMPLE 26 The nickel salt of N-[(2-hydroxyphenyl)(methyl)-methylene]-4-dodecylaniline, prepared as described in Example 10, alsowas evaluated in another sample of the polypropylene described inExample 23. The data are reported in the following table, which alsorepeats the results obtained when using a sample of the polypropylenewithout the inhibitor.

TABLE 5 Weather-Ometer Outdoors Additive Induction Period InductionPeriod (Hours) (Days) None 48 54 1% by wt. of nickel salt of N-l(2-hydroxyphenyl) V V V (mothyl)methylene]-4- dodecylaniline 1, 032 227Here again, it will noted that the inhibitor was effective in retardingdeterioration of the polypropylene.

EXAMPLE 27 The nickel salt of N[(2-hydroxy-4-methoxyphenyl)-(phenyl)rnethylene]-4-dodecylaniline, prepared as described in Example12, also was evaluated in another sample of the polypropylene describedin Example 23. The results of these evaluations and of a sample of thepolypropylene without inhibitor are reported in the following table.

TABLE 6 Weathcr-Ometer Outdoors Additive Induction Period InductionPeriod (Hours) (D y None 48 54 1% by wt. of nickel salt of N-[(Z-hydroxy-i-methoxyph en yl) (phenyl)methylenel--dodecylaniline 936274 Here again, it will be seen that the inhibitor served to retarddeterioration of the polypropylene.

EXAMPLE 28 The nickel salt of N-salicylidene-4-dodecyloxyaniline,prepared as described in Example 18, also was evaluated in anothersample of the polypropylene described in Example 23. The results ofthese evaluations are shown in the following table, along with theresults obtained in evaluating the polypropylene without the inhibitor.

TABLE 7 Weather-Omcter Outdoors Additive Induction Period InductionPeriod (Hours) y None. 48 54 1% by Wt. of nickel salt of N-salicylidene-4dodecyloxyaniline 1,896 233 The data in the above tableshow that the inhibitor is effective in retarding deterioration of thepolypropylene.

EXAMPLE 29 are reported in the following table. Also included in thetable are the results obtained when using the polypropylene free ofadded inhibitor.

From the data in the above table, it will be seen that the inhibitor waseffective in retarding deterioration in this different commercialpolypropylene.

EXAMPLE 30 This example reports evaluations made in a special batch ofcommerical solid polyethylene. As hereinbefore set forth, a specialbatch of the solid polyolefin was obtained free of any inhibitors inorder that it may be used as a proper control sample to evaluate theeffect of different inhibitors. The solid polyethlyene is of the highdensity type and the inhibited product is marketed commercially underthe trade name of Fortiflex by the Celanese Corporation of America.

A sample of the polyethylene without inhibitor and a sample of thepolyethylene with 1% by Weight of the nickel salt ofN-salicylidene-4-dodecylaniline, prepared as described in 'Example 2,were evaluated in both the Weather-Ometer and in outdoor exposure in thesame manner described in Example 23. The results of these tests arereported in the following table.

TABLE 9 Weather-Omcter Outdoors Additive Induction Period InductionPeriod (Hours) (Days) N one 192 42 1% by wt. of nickel salt of N-salicylidenet-dodecylaniline 3, 408 401 EXAMPLE 31 The nickel salt ofN-o-vanillidene-4-dodecylaniline, prepared as described in Example 8,also was evaluated in another sample of the polyethylene described inExam- 7 ple 30. The results of these evaluations are reported in 1%reading of 32 to a reading of 88 after 381 days. It will be noted thatthis sample had not reached an increase in 100 units and the evaluationaccordingly is being continued.

EXAMPLE 32 The nickel salt of N-[(2-hydroxyphenyl) (methyl)-methylene]-4-dodecylaniline, prepared as described in Example 10, alsowas evaluated in another sample of the polyethylene described in Example30, with the following results:

TABLE 11 Weather-Ometer Outdoors Additive Induction Period InductionPeriod (Hours) (D None 192 42 1% by wt. of nickel salt of N[(2-hydroxyphenyl)- (methyl)methylene]-4- dodecylaniline 2, 256 381 Hereagain, an increase in 100 units had not been reached in the samplecontaining inhibitor which was exposed outdoors and the evaluation isbeing continued.

EXAMPLE 33 The nickel salt of N-[-(2-hy-droxy-4-methoxyphenyl)(phenyl)methylene]-4-dodecylaniline, prepared as described in Example12, also was evaluated in another sample of the polyethylene describedin Example 30, with the following results: a

Here again, it will be noted that the inhibitor was very effective inretarding eterioration of the polyethylene. The sample containinginhibitor which was exposed outdoors increased in carbonyl reading from23 to 85 in 381 days and, accordingly, the evaluation is being continuedbecause the sample had not developed an increase of 100 numbers incarbonyl content.

EXAMPLE 34 The nickel salt of N-salicylidene-4 dodecyloxyaniline,prepared as described in Example 18, also was evaluated in anothersample of the polyethylene described in Example 30, with the followingresults:

. TABLE 13 the following table, along with a repeat of the results Iobtained with samples of the polyethylene free of added weathepometerOutdoors lnhibltor. Additive Induction'Period Induction Period 7 (Hours)Days) TABLE 10 7 None 192 42 Weather-Ometer Outdoors 1% y W of luckelSalt of N" Additive Induction Period Induction Periodsflliqyhdene-tdodecy 3" (Hem-S) (Days) aniline 2, 736 281 None 192 42 I1 d td 100 1%byWt 0fmcke1Sa1tofN n e .samp e expose ou oors, an increasein q-va i d d d y 3 381 number in carbonyl content has not been reachedand the hue evaluation is accordingly continuing.

It will be seen that this inhibitor was extremely effective in retardingdeterioration of the polyethylene. Furthermore, the sample containinginhibitor which was exposed outdoors increased in carbonyl content froman initial EXAMPLE 35 p T he nickel salt of N-[(2-hydroxyphenyl)(methyl)methylene]-4-dodecyloxyaniline, prepared as described in Example20, also was evaluated in another sample of the a continued.

17 polyethylene described in Example 30, with the following results:

The sample containing inhibitor which was exposed outdoors had notdeveloped an increase of 100 numbers in carbonyl reading and,accordingly, the evaluation is being EXAMPLQJ This example reportsresults of evaluations made in a low density polyethylene commerciallyavailable from the Visking Corporation. These evaluations were made inthe same manner as described in Example 23. The results of tests madewith a sample of the polyethylene without the inhibitor and with asample of the polyethylene containing the inhibitor are reported in thefollowing table.

TABLE Weather-Ometer Outdoors Additive Induction Period Induction Period(Hours) (Days) None- 96 28 1% by wt. of nickel salt of N-salicylidene-ei-dodecylaniline 3, 360 401 Here again, it will be seenthat the inhibitor was very effective in retarding deterioration of thepolyethylene.

EXAMPLE 37 The nickel salt of N-[(2-hydroxyphenyl)(methyl)methylene]-4-dodecyloxyaniline, prepared as described in Example20, also was evaluated in another sample of the polyethylene describedin Example 36, with the following results:

As hereinbefore set forth, the inhibitor of the present invention may beused along with other additives. This example reports the resultsobtained when using 1% by weight of the nickel salt ofN-salicylidene-4-dodecylaniline, prepared as described in Example 2,together with 0.5 by weight of B.H.T. (2-tert-butyl-4-hydroxytoluene) inanother sample of the polypropylene described in Example 29. Theevaluations in the Weather-Ometer were increased from 1200 hours whenusing the nickel salt alone to 1824 hours when using the mixture ofadditives. Similarly, the outdoor exposure evalutions increased from 268days to greater than 312 days when using the mixture of additives.

EXAMPLE 39 The nickel salt of N-salicylidene-4-dodecylaniline, preparedas described in Example 2, is used as an inhibitor in solidpolybutylene. The inhibitor is incorporated by hot melt addition of theinhibitor to the polybutylene being heated and pressed on a conventionaltwo-roll steam 1% heated mill. The polybutylene sheets then areheat-compressed to a thickness of mils, cut into plaques of 1 /2" x 1/2" and mounted in plastic holders. The plaques are evaluated both inthe Weather-Ometer and by outdoor exposure in the manner hereinbeforedescribed in detail. The addition of the inhibitor serves to effectivelyinhibit carbonyl development.

EXAMPLE 40 The nickel salt of N-o-vanillidene-4-dodecylaniline, preparedas described in Example 8, is used as an inhibitor in polystyrene. Theinhibitor is incorporated in a concentration of 0.5 by weight inpolystyrene by partly melting the polystyrene and incorporating theinhibitor in the hot melt. The polystyrene containing the inhibitor isof improved resistance to deterioration by ultraviolet light and due tooxidation.'

EXAMPLE 41 The nickel salt of N-salicylidene-4-dodecyloxyaniline,prepared as described in Example 18, is utilized as an inhibitor inpolyvinyl chloride plastic. Here again, the inhibitor is incorporated bypartly melting the polyvinyl chloride plastic and incorporating theinhibitor in the hot melt in a concentration of 1% by weight. Thisserves to inhibit deterioration of the polyvinyl chloride plastic due toultraviolet light and oxidation.

EXAMPLE 42 The nickel salt of N-salicylidene-4-dodecylaniline, preparedas described in Example 2, is used in a concentration of 0.5% by weightin nylon. The inhibitor is incorporated in a Banbury mixer and the nylonis formed into fibers in a spinnerette. This serves to inhibitdeterioration of the nylon due to ultraviolet light and oxidation.

I claim as my invention:

1. A compound selected from the group consisting ofN-(2-hydroxyphenylmethylene)-Y-arylamine in which the aryl contains from1 to 2 carbocyclic rings and Y is selected from the group consisting ofhydrocarbyl and hydrocarbyloxy of at least 3 carbon atoms and metalsalts thereof in which the metal is selected from the group consistingof nickel, copped, cobalt, lithium, antimony, cadmium, lead, tin,uranium, vanadium, zinc, iron and mercury.

2. N-(2-hydroxyarylmethylene)-Y-arylamine in which the aryl containsfrom 1 to 2 carbocyclic rings and where Y is selected from the groupconsisting of hydrocarbyl and hydrocarbyloxy of at least three carbonatoms.

3. A metal salt of N-(Z-hydroxyarylmethylene)-Y-arylamine in which thearyl contains from 1 to 2 carbocyclic rings and where Y is selected fromthe group consisting of hydrocarbyl and hydrocarbyloxy of at least threecarbon atoms and the metal is selected from the group consisting ofnickel, copper, cobalt, lithium, antimony, cadmium, lead, tin, uranium,vanadium, zinc, iron and mercury.

4. A nickel salt of N-(Z-hydroxyarylmethylene)-Y- arylamine in which thearyl contains from 1 to 2 carbocyclic rings and where Y is selected fromthe group consisting of hydrocarbyl and hydrocarbyloxy of at least threecarbon atoms.

5. N-salicylidene-4-alkylaniline having from about 5 to about 20 carbonatoms in said alkyl group.

6. A nickel salt of N-salicylidene-4-alkylaniline having from about 5 toabout 20 carbon atoms in said alkyl group.

7. A nickel salt of N-salicylidene-4-alkoxyaniline having from about 5to about 20 carbon atoms in said alkoxy group.

8. N-o-vanillidene-4-alkylaniline having from about 5 to about 20 carbonatoms in said alkyl group.

9. A metal salt of N-o-vanillidene-4-alkylaniline having from about 5 toabout 20 carbon atoms in said alkyl group and in which the metal isselected from the group consisting of nickel, copper, cobalt, lithium,antimony,

20 cadmium, lead, tin, uranium, vanadium, zinc, iron and ReferencesCited mercury. NIT D P 14 N-[(2-hydr.oxy-pheny1)(a1ky1)methylene]4-alky1 U E STATES ATENTS aniline having from about 5 to about 20 carbonatoms in 2355257 8/1944 Badeflscher 260429 said alkyl group.

5 1 i 11. N[(2 hydroxyphenyl) (pheny1)rnethy1ene] 4- TOBIAS LEVOWPrimary Examiner alkylaniline having from about 5 to about 20 carbon W.F. W. BELLAMY, Assistant Examiner. atoms in said alkyl group.

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OFN-(2-HYDROXYPHENYLMETHYLENE)-Y-ARYLAMINE IN WHICH THE ARYL CONTAINS FROM1 TO 2 CARBOCYCLIC RINGS AND Y IS SELECTED FROM THE GROUP CONSISTING OFHYDROCARBYL AND HYDROCARBYLOXY OF AT LEAST 3 CARBON ATOMS AND METALSALTS THEREOF IN WHICH THE METAL IS SELECTED FROM THE GROUP CONSISTINGOF NICKEL, COPPED, COBALT, LITHIUM, ANTIMONY, CADMIUM, LEAD, TIN,URANIUM, VANADIUM, ZINC, IRON AND MERCURY.